Muffle furnace



sept. 29, 1925. 1,555,228

D. S. ODONOVAN MUFFLE FURNACE Filed Feb1 29. 1924 Patented Sept. 29, 1925.

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SIGNOR To yonoirovar i nunnaens LIMITE-.m org JoHA-N'N'Esnune, sonnen .ann-ICA.

A MUFFLE n'rnnnon.

`Application led February 29,219724. Aberial No. 96,047.

'o all whom'z't may conce/Mi.'

"certain new and useful Improvements in Manie Furnaces, oitl winch tlreioilowing is a specifica-tion.

lThe present invention has reference to inullle furnaces and more `particularly to such Vfurnaces in which a'series of muiiies (or an equivalent long inutile) is arranged in a long flue or heating chamberso astobe heated tol progressively vdiffering temperatures, whereby articles placed inthe inutiles and `shifted step by step through thezserresf ,are subjected to vgradual heating.

j The purpose oit'theinvei'ition is 'to enable the heat gradient in the maille series to be adjusted Vas required, more particularly by relatively raising the temperature at the cooler end of the series,.which tends tol become unduly cool.

T he invention is illustrated in the accompanying drawings in wh'ich- Fig. I is a longitudinal section of a furnace, and i f f Fig. II is a transverse section on II-II, sie. I. i` u 'lhe source of heat is indicated by a firebox 2 situated at one end of the furnace structure 3. l is a flue leading from the lire box and 5 a long inutile chamber disposed parallel with the flue. Muiiles 6 are supported in the wall of the Inutile chamber and project transversely into said chamber. rlheir inner ends are closed and their outer ends open to receive the articles to be heated e. g. rock drill tools ll.

rlhe muftles are arranged in a row or rows; the said row or rows, together with the inutile chamber and the flue, being preferably disposed horizontally so that a number or" drills or other bodies positioned in the muilles are convenient of access tor shitting them stepby-step through the Inutile series.

Two horizontal rows (6a to 6b and 6c to 6d) of muliles are shown, projecting in from opposite sides of the furnace structure and positioned one above the other.

The division between the line and the muiHe' chamber is provided by a number of tire-brick slabs 7. These rest on corbels 8 and can be slid along the same to any destructure.

sired; positions and provide'openin-gs such-.as

*9, 9, 9", etc., for t-hefurnaeeugasesto pass trom the lire box and' the -fluef to vthetn'iu'tlle chamber'. :The used gases pass away'by a vchimney 10 tdistant" from the' :lire box 1 2.

The Ageneral y'etl'ect of passing Ythe furnace gases through the series of mui'ilesi'rom .the source of heat 'disposed at one-end of the series, is to establish a temperature gradient throughout the series, the `inutiles 6a, -6c most distant:l fromy thelirebeing least heated, and the temperature increasing up to the' mutl'les 6b,l 6d nearestthe lire,` -whichattaini the -high- Aest v'tei'npeiature y' Accordingly an "article placed iirst in the'mullefaor (ibl'andthen shiiftedpat intervals into eachotthermuiiles ot its row, is' heatedto` the-'l'tina-ltemperature to a temperature excessivelyl higher than its owin which would ytend-to fdeteriorate its Itis^preferredyto Ause `a large number of inutiles in each series,\'bothf in {order that the temperature Lstepsshouldfbe small and also to enable the; metal-:articles: to lbe treatedin considerable numbers 'without forcing the rate of heating.

The various openings which conduct the hot gases into the muille chamber are s0 adjusted that whilst a substantial proportion of the furnace gas passes directly into the inutile chamber through the relatively large opening 9, other proportions of the gas are ted in at different openings 9a, etc., farther away from the lire, to reinforce the heating effect in the chamber at those points; such reinforcing gases having been but little cooled in comparison with the directly admitted gases which have already passed through some of the Inutile series.

It is advantageous to position the muffles closely, together thereby setting up a material resistance to the gas low which is utilized to adjust the gas distribution as desired.

The effect is to relatively raise the temperature of the cooler parts of the maille series, and it is possible in this way to so adjust the temperature gradient throughout the series, as to attain the maximum speed of movementof the articles through the furnace, whilst exposing them to the minimum temperature increments at each step. It is evident that articles which have been heated and require to be cooled at a regulated rate .navinslmnrsnnos .ononoven or VoGnLrioN'rnrN,aman-sane@SQUTH Armen, As-

may be passed through a similar muffle series in the reverse direction with similar advantageous results.

It is found that with a furnace constructed as shown in the drawings the temperature gradient may be varied by increasing or decreasing the draft and at the same time readjusting the openings 9, 9a, etc., without materially varying the final temperature exhibited by the muflies. 1When the character of the work to be do-ne varies from time to time, the slabs are arranged adjustably as shown; but it will be evident that for carrying out operations of an unvarying character, the slabs may be permanently positioned to provide the reinforcing openings required.

I claim l. A muffle furnace comprising a muiile chamber, a source of heated gas feeding the mufl'le chamber so as to produce a temperature gradient therein, inutile means arranged in the inutile chamber to be heated to different temperatures corresponding tothe temperature gradient, there being a direct inlet for gas from the source to one end of the muflie chamber and at least one indirect inlet modifying the temperature gradient which the directly admitted gas tends to produce.

2. A muiie furnace comprising a single source of heated gas, a long muile chamber through which gas from the source passes (in substantially one direction) whereby a temperature gradient is set up in the chamber, a flue fed from the source and means aording communication from the flue to the chamber for passing reinforcing supplies of gas from the flue into the inutile chamber.

3. In a muffle furnace, a source of heated gas, a long muflle chamber fed at one point directly from said source, a chimney arranged toexhaust the whole of the gas from a point in the muflle chamber distant from the point at which the gas is fed thereto, a Hue fed by said source, and means affording communication between the Hue and the mufie chamber for passing supplementary supplies of gas into the latter.

4. ln a inutile furnace, a source of heated gas, a mufHe chamber, a flue parallel with the same and movable means providing adjustable openings from the flue to the chamber.

5. In a muflie furnace, a source o-f heated gas, a muftle chamber, a flue beneath the same, slab supports and slabs loosely carried on said supports and interposed between the flue and the chamber.

6. ln a muiile furnace, a fire box, a long horizontal mufle chamber fed at one end directly from said fire box a chimney at the other end of the chamber, a'series of muffles extending through the chamber wall transversely into the chamber, al iue beneath the chamber and slabs separating the flue fro-m the chamber.

In testimony whereof I affix my signature.

DAVID STANISLAUS ODGNOVAN. 

